Compass unit



DIGEsfs 2 0 2 Dec. 12, 1944; L. c. MILLgR 2,364,908

coMPAss UNIT Original Filed July 20, 1939I 2 .Sheets-Sheet 2 Patented Dec. 12, 1944 COMPASS UNIT Leonidas C. Miller, Los Angeles, Calif., assigner, I, by direct and mesne assignments, of one-half to Eastman Oil Well Survey Company, Dallas,

Tex., a corporation of Delaware, and one-half to Eastman Oil Well Survey Corporation, Long Beach, Calif., a corporation of California i Original application July 20, 1939, Serial No. 285,597, now Patent No. 2,317,632, dated April v 27, 1943. Divided and this application March 6, 1942, Serial No. 433,545 f This invention relates to new and useful improvements in compass units.

This application is iiled as a division of my co pending application, Serial No. 285,597, iled July 20, 1939, now Patent No. 2,317,632, dated April 27, 1943. e l f I One object of the invention is to providean improved compass unit which is particularly adapted for use with a well survey instrument, such as is illustrated in the above referred to application, but which may be employed elsewhere. Y

An important objectl of the'invention is to provide an improved compass unit which is arranged to control the operation of an electric motor which, in turn, may .control the position of a movable element, whereby said. ,e lement may be i1 1iiaintained in a predetermined direction or posi- A particular object of the'invention is to provide an improved compass unit including a hemispherical compass element which is provided with means on its upper surface adapted to co-act with a light responsive means, whereby the position of the compass element controls the actuation of thel light responsive means, with the result that the position of said compass element may be utilized to indirectly control or actuate a movable member through said light responsive means.

A further object of the invention is to provide a simplied mounting for the compass element, whereby said element is maintained in a, horizontal Diane regardless of the inclination of the casing within whichthe compass unit is mounted? construction, whereby the device may readily;i withstand excessive vibration, .shocks and jar without affecting the efficiency of the compa operation.

`Still another object of the invention is to priavide an improved compass unit, of the character described, wherein a compass element having a. substantially hemi-spherical shape is employed; the entire upper surface of the element, with the exception of a radial section thereof, being either of a light reflecting or non-reilecting material, with the radial section being of a material differerft from the remainder, that is, if the surface is non-reflecting, the section is light reflecting and u tilized to co-act with and actuatea light responsive means. f

' A particular object f the invention is to provide an improved compass, of the follow-up type which said mounting and unit also being sturdy in .v

vice versa, whereby the compass element may be position of inclination from the vertical to the horizontal; the device also having means for immediately moving said device to its predetermined set position in the event the instrument within which it is mounted is rapidly rotated,4

whereby ecient operation under any conditions is assured. f j The construction designed to carry out the invention will be hereinafter described together with other features of theinvention. The invention willbe more readily understood from a reading of the following specification andv by reference to the accompanying drawings, as anexample of the invention is shown, and wherein:-

Figure 1 is a transverse, vertical, sectional view. of a-compass unit constructedin accordance with the invention, y f t f A Figure 2 is a-horizontal, crosssectional view, taken on the 1ine'2-2 of Figure 1, l, Figure 3 is a transverse, vertical sectional view. oi the portion of a well instrument within which the compass unit may be mounted,

Figure 4 is a continuation of Figure 3 and show- "ing the compass unit in position within the lower end of the instrument, and Figure 5 is a wiring diagram of the parts shown in-Figure 4 and illustrating the controlof an electric motor by the compass unit.

In the drawings, the numeral I0 designates a tubular shell or casing which has its lower en d closed by a block II which .is preferably securedwithin the lowerportion of the shell by suitable screw-threads I2. The upper end of the shell-is closed by a cap member I3 which is threaded into the shell'and which is formed with a down. wardly extending, conical sleeve I4. The sleeve `is` located axiallyonV the cap member, being formed integral therewith, and said sleeve is re- .may retain a suitable fluid or liquid for damping the movement. of a compass C which is mounted therein; the level of the liquidwithin the compass chamber is spaced from the cap member I3 to provide an air space thereabove and reduced ports or orices .I3a extend through the sleeve I4 immediately below the window I6, whereby the formation of air bubbles below the window isobviated.. Theprovision-of the window I6 permits the entry of light rays into the interior, as

is' constructed so as'tofoperate efficiently at any 5 will be hereinafter explained.

For mounting the compass C within the shell,

the block Il in the lower portion thereof isi'ormed with .an axial bore I1 l.which extends. entirely therethrough. -A shaft [8 `which .extends axially of the bore is mounted therein on suitable ball bearings I 9, which are located at the upper and lower portions of the bore, the upper bearings engaging an internal annular shoulder while the lower bearingsiareheld implaceby a flanged retaining cap 2l. 'Boe extreme-upper end of the shaft I8 projectseabove thezwpof the block II and is provided with external Ascrewthreads, whereby an arcuatesupportmg'bracket or collar 23 may be secured thereto. :Itwiil be evident that when the bracket isssecuredf-to the upper end of the shaft, said' hradretiis freelylrotatable within the shell I0. .Znbmcketwhidiis arcuate in shape is provided with an upstan'dlng. substantially semi-circular ange which is preferably integral therewith, this flange' being clearly showninlFigure. f

FA weight 252 isffastenedtwithinthe: upstandng flange 'I4-and is locatedvat'one sideof the bracketl. This weight'functions-to rotate thebracket in accordance-with any inclination ofther'shell N. It will AbeobVIous that when'thesheil is inclined from the vertical, the weight 25 will always tend toifall to the low vside and'ftheretore, the bracket!! will be rotated' toa'y predeterminedxposition relative to suchlowlide.

The compass C` includes "a Lsemiaspherical base Il andthis'base is 'preferably formed "of solid material. 'Diameti'ically Y"vlliwsed, upstanding ears TI are'formed intesrallwlth the base and are adapted to be secured to'ihe'iiange4 adjacent the ends yof said aange, the ears being'connected to the flange by pivot pins 28. Theplvot pins .28 are'4 misalined'substantlally-'SU degrees from the axis of the weight, whereby whenfthe'shdl I0 is inclined'the/horizontal'axisf the pivot-pins will always'be located'in=a plane which is at a right angle to-the direction of the inclination. When theshell is inclined, the'upstandlng iange 24^of the bracket 23'is,-of course-also inclined but since the base 2E is-'welghted and: is pivotally secured'to the ilange'24,'-said-base will swing on the pivot pins :2l and' thereby, the upper surface of the base'will be maintained in' al true horizontal plane.

"An upwardly extending suspension'or pivot pin 29 ismadeintegral-with a supporting plate 30 and-said plate is adapted-tent within a; recess II formed inthe upperisurface of the 'base member It. 'The recessis-formed'at thecentrarportion f the base-so 'that the; pin -29 is 'located axially of saidbase when` the plate is withinthe recess. Aepending 'stud 'l2 is formed on the-plate III and engages `within *a eountersunk opening 33 provided inthe base. Assuitable fastening screw 34 is'threaded-intothe stud so as'to fasten the gatl and pini! inposition on the base mem- A 'semi-'spherical compass element or shell 35 ismounted'so as tote-freelyrotatable upon the suspension or pivotpin' 29. v".the'shell'is' secured to the `eiosed'upper end 'cfa-supporting sleeve n, which sleeve isadaptedto-'engageover the pin-29. A suitable "Jewel 31 may `be mounted within' the'upper 'end vof thefsleevezto provide 'a bearmg'which-rests uponthe uppefpcinted end ofthe-pin '29. As-iscleariyshown in Figure l, the'sleeve is of a diameterconsideraltrly Ygreater than thepln N'So'as to bepaced therefrom' and pennit a free Jrotations -of the compass `element matin@ within the shell I5 and are responsive to the earths magnetism, whereby the shell is rotated toapredetermined position .relative to azimuthalnorth. Upwarmdisplacement of the n shell and of the sleeve I8 relative to the pin 29 isgprevented by a anged keeper 39 which is se- Y cured to the plate and which overlies an an- `^nuiar ilange 40 formed on the lower end of the udeevef.

.-'Ihe-.upperssuraoe of the shell or compass ele- ;mentSl is dispoaedimmediately below the curved window I6 whichis carried by the cap member I3. This'upper-surface of the shell is of a dull nonereilectingsurface except for a narrow strip .15 tor'barofdight-.reecting material 4I. The strip or barcextendszfrcm the center of the shell (Figmrel-Zlztothenutereedge thereof and is disposed :on theshelllsas to constantly point in a predetermineddirection. For the plirPOses of this de- 20 scription,`it will be presumed that the reflecting bar: or: strip 4I.isaiways pointingnorth, although -it could be arranged'zonsthenpper surface of the shell'toipointzinntherfdirections. 'LItwill be obvious thatm'when said' shell is lnclinedgthe oom- 25 pass element flisamaintainedrinzatrue horizontal plane and functions to control the position onxiirectlon of the'reecting strip or-sbar'l4l. VReeardlesszof any. rotation ofxthe'sshell, the compass ciment-I5 wiilmaintain thestripin suchprede- V80 terminedidirection.

.-'Ihecompass unit Cis arranged-to co-'act with a light projecting and a light responsive means wfcontrol :theactuation-ofy said' light responsive means. The lightA proiectingmnd light responsive so means is illustrated in Figure4'and islshown as mounted'withina eylirdricalcasingf-n.- which casing isrsubstantiallyrthefsame size'vas'the shell III. This means includes artubi'nar lensecarrying sleeve 43 and this sleeve is disposed at one side of-the 4.0 opening formed bythe-'conical sleeve I`4 lon the closure orcap-member I3 of'the'shell I0. "Ihe sleeve is fastened or supported on'suitabie plates which extend across the interiorof the casing 42. 'A- prism 45 is mounted'adlacent the lower 45 eudof the sleeve 43 and4 serves'todirect lightrays which are passing-through the'sleevef43,as'wili be explained,vdownwardly"through the Window It vand ontov the upper-'surface of the compass element or shell. lAsisschematica]ly illustrated'inFigure 5, the'sleeve 14I-hasa pair of condensing lenses '46 at its lower'end, while a sate '41, ofthe usual construction-is mounted I above these lenses. Above the'sate-.upper lenses 48 are lmounte'dwitl'xinthesleeve. Secured to the uppermost plate-44 which'supportsthe sleeve 43, is a lamp socket 49- within which'anelectric lamp or lightsource lisdisposed. When `the lamp is ilh1minated,`light' rays pass-'downwardly through the tubular sleeve 43 and through the so lenses, which `ooiicei'xtrate-the light rays on the prism 45. The'pxism then 'directs the light rays through the window Il `and ontothe light reilectingstrip or' bar 4I 'on'the upper-'surface of the compasselement.

The light rays which'strlke-theli'ght reflecting striporbar 4I are ureflected upwardly therefrom and-onto a twinllight=sensitive element, such as altwin photo tube 5I, which'includes photoelectric cells 52and 53 '(Figure '5). A prism 54 is 70 interposed between the-compass and the twin photo-tube, both'of 'these-elementsbeing mounted in one of the supporting plates 44 whichextend across the interior of the-.casing 42.

Under Anormal conditions, whenthecompass is or shell on said pin. The'usual'magnets 38 arci 75 at'x'est withthe strip`4I poiutingnorth, the light LAGIIIIIICI rays from said strip are directed between the photoelectric cells -52 and 53, as is indicated by dotted lines in Figure 2. At such time, each cell is receiving an equal amount of light. Each cell maybe connected to a suitable electrical apparatus, such as a relay, which may control a motor winding, or other electrical apparatus. Thus, if both cells are receiving the same amount of light, neither relay will be actuated because the equal distribution of the light will result in neither cell receiving sufficient light to actuate its electrical apparatus. However, if the compass shell or element 35 moves with relation to the photoelectric cells so as to cause more light to strike one cell, then the electrical apparatus to which that cell is connected will be actuated. Such actuation may be utilized to bring the two photoelectric cells back into alinement with the reecting strip or bar 4|.

The apparatus described herein may be used for any desired purpose and for the purpose'l of illustration, it is shown herein as controlling the position of an azimuth contact of a well survey instrument. Referring to Figures 3 and 4, the shell I is mounted in the lower end of a housing 55 which housing has a depending pin 56 at its lower end and an upstanding pin 51 at its upper end. These pins am mounted in bearings 58 which are'supported in the outer case 59 of the survey instrument and in this manner, the housing 55 is freely rotatable within said case. The shell I0 which houses the compass unit is fixed or fastened within the housing so as to be rotatable therewith but not independently thereof. The light source, together with the lens .system and light responsive cells are mounted within the housing 55 above the compass unit,

' the casing 42 of these parts being supported on an annular ring 60 secured within the housing 55. The upstanding pin 51 is provided with an insulated collar 6I which has an azimuth contact 52 secured to its upper surface and it is desirable to maintain this contact in a predetermineddirection at all times. The insulated collar 6I may also have contact rings 63 on its outer periphery, which rings may be engaged by brushes 6l so that current may .be conducted downwardly to the electrically operated parts. The azimuth contact 62 is so mounted on the collar 5I that it is in vertical alinement with the radially extending reecting strip or bar 4I on the compass element 35.

The survey instrument is ordinarily lowered by means of a cable or wire line, whereby the outer case 59 of said instrument may rotate as it is being lowered. Obviously, the instrument will assume an inclination in accordance with the inclination of the bore. 4In order to accomplish a proper survey, it is desirable that the azimuth contact 62 be maintained in a predetermined direction at all times, regardless of the rotation of the case 59 or regardless of any inclination of the well bore.

' For imparting a rotation to the housing 55, a follow-up motor 65 is provided and is supported on a suitable transverse plate or deck 66 which is located in the upper portion of the housing 55. The motor shaft has a drive pinion 51 which has connection through va reduction gear train 68 with a friction drive wheel 69. The wheel is mounted at one side of the housing 55 and its periphery rides upon the wall of the case 59 of the survey instrument. Manifestly when the follow-up motor 65 is actuated to rotate the wheel in one direction or the other, said wheel imparts a rotation to the housing 55, such rotation being relative to the outer case 59. Since the azimuth contact 52 is carried by the upstanding pin 51 of the housing 55, any rotation of the housing will result in a rotation of the contact 62. Thus, regardless of the position of the outer case 59, the position of the inner housing 55 and of the azimuth contact 62 carried thereby can be maintained through the operation of the follow-up motor 65.

'Ihe twin photo tube 5I, which is responsive to the light being reected by the compass element 35, is arranged to control the operation of thev follow-up motor 65. The motor has a double winding 65a and 65h so that its shaft may be rotated in either direction to drive the pinion 61 in either direction. 'I'he electrical circuit, in which the twin photo tube and the motor are connected, includes a twin amplifying tube lll, a power transformer 1|, and a trio of relays-12, 13 and 14, these elements :being mounted within the housing 55 on suitable transverse supports which are disposed between the casing 42 and the follow-up motor 65.

.The photoelectric cell 52 is arranged to close the circuit through the relay 12 to the winding 65a of the motor to rotate the motor shaft in one direction, while the other photoelectric cell 53 is adapted to close the circuit to the other winding 65h of the motor through the relay 14. Thus, if the cell 52 is receiving more light, as reected by the light reflecting strip 4l of the compass, then the winding 65a is energized to rotate the shaft of the motor 65 in one direction; if the cell 53 is receiving more light, then the motor shaft is rotated in an opposite direction.

'As has been explained, the light responsive cells 52 and 53, are normally located, one on each side of the light reflecting strip 4|. With the compass at rest and the strip 4| pointing north, the azimuth contact 62 is also pointing north and at such time, the light rays from the strip 4I are directed between the cells 52 and 53, with each cell receiving an equal amount of light, such amount being insuflicient to actuate the relays controlling the motor windings 65a and 65h. If the compass element or shell 35 of the compass moves with relation to the photo tube so as to cause more light to strike one cell, then the motor winding controlled by that cell is actuated and such actuation, results in a rotation of the casing or housing 55 to automatically cause alinement of the cells 52 and 53 with the strip 4I. In other words, the follow-up motor 65 rotates the casing in one direction or the other so that the relative position of the casing or housing 55 to the compass element 35 is maintained.

When such position is maintained, the azimuth contact 62 is held in a proper position with relation to a predetermined direction.

It is not believed necessary to describe in detail the wiring diagram shown in Figure 5. The relay 12 controls electrical contacts 12a which close an electrical circuit to .the winding 55a, while the relay 'I4 controls contacts 14a which close an electrical circuit to the winding 65h. It might be noted that the relay 13 isl merely an emergency relay. It might occur in some instances that the outer case 59 may be rotated very rapidly, in which case the compass shell 35, in seeking north, would move the reecting strip 4l completely from beneath both of the, cells 52 and 53, with the result that neither could operater itsrelayto realine. said cells withl the strip. In the. event: that.. this should occur; thej emergency. relay 13 comes into. operation. As'

shown in Figure 5, the relay r34 isconne'ctedto: the -relays 12 andll' by a wire 13a and lsrarcranged` to control contacts 13b. These: contacts'.

tacts 13b open and so long as either or'both cells.

are, receiving light. the circuitthrduglrthese conFl tactsis open. Howevenin the event no light. strikes. either cell, the. relay-13; is'.-deeenergizexl:v allowing; the contacts. 13b to closefthecimuintm the motorwinding 65h, whereby the motor shaftf is rotated inone direction to.impar.t:rotad:ion tothe casing. Such rotation continu; until one-' of. the cells 52 or 53 again receivesthe; reflected. light, at which ytime the. cellszagainactuate their: relays to ,aline the strip .4l with ,thephotoelectricy tube I. As soon as the photoelectricoells again come into operation the. relay 1s is'rerenergized to open its contacts 13b.

From the foregoing, it win 15e-seen that the.

compass unit co-acts with the light responsive; means to control a. suitable electrical apparatus.- In theadaptation .of the inventionherein illustrated, the unit controls the position'. ofA an azimuth contact in a wellsurveyinstrument; How-v ever, since the photoelectric cells 52 and 53 may. control the operationof relays, such relays may, in. turn, control any desired electrical circuit to perform any desired function. For this reason, the. invention is not to be limited to use in the particular type of4 survey instrument herein disclosed. The compass unit is very sturdy-in con--v struction and is mounted so that thecompass shell .35 operates ina true horizontal plane under all conditions. Adamping uid or,liquid is introduced into the -shell l0 and surrounds the movable1 compass elements sov as to damp the movement thereof. Although the lens system and twin. photo tube arrangement have been il lustrated. as. mounted within aseparate casing 42. which is disposed above the shell I0 of the compass unit, it is. obvious that these parts may all. be` mounted within a single tubular casing or. shell so. as to provides unitary structure. Also, the invention could be .carried out by making the. entire surface of the compass element of a light reflecting material while the strip 4l could be made of a non-reflecting material. In thisA case, the operation would be the same.

The. foregoing description of the invention is. explanatory thereof and various changes in the size,.shape and materials, as well as in the details. of the illustrated construction may be made, within the scope ofthe appended claims, without departing from the spirit ofA the. invention.

What I claimand desire.to. secure by Letters..

Patent isz.

1. The combination with amovableelement of: a compass unit for controlling the position of said element, said unit including, a housing, a compass member mounted in the. housing and. responsive to the earths magnetism, the compass member being substantially semi-spherical in shape with, its outer curved surface being of.

non light-reflecting material, a. strip 4of 1ight reflecting material secured latitudinally to the outersurfaceof the member and extending from the pivotaxisl tothe odge` thereof, said? strip being maintained in' a predetermined'l directionY by'said compass member, a light source-above the compass member for directinglight rays. onto 5- the uppersurf'ace thereof, and' actuating-meanst connected with the movable element-for control#- ling the movement of the same,- said meansf being responsive to light rays reflected by said'h strip of reecting'material, whereby the= actuat l0ing means co-acts with the radially extending 20.' pass member being substantially semispherical in shape: witlrits: outer. curved mil nonlight-reiiecting material. a= strip: ot' li'ght'.re.- fleeting material secured latitudinall'y to; outer surface of themenrberand extendingfmnn the pivot axis. to the'edge'thereof, said stripbeing' maintainediin a predetermined direction'. by said: compass member, a; pair of:1ight responsive cellar above the compass memberand connected with; the movable element for controllingamovement ot 30- said element, and a light sourcefabove the;com.=-

pass member for directing light raysronto the: outer surface thereof, whereby whenthe rays strike the reflecting strip on said member. said: rays are reflected to the light responsive-means,

" to actuate the same and thereby control. the' position of the movable element in' accordance with thev position of the-strip onthecompass.` member, said light'reecting strip being normally: disposed between' the' light responsive cells.- so. that said cells are normally inactive because of'. insuflcient light and. it is only 4vvhennsaidstrip moves from its intermediateposition with respectY to. said cellsthat one or. the other ofthecells are.v operated to impart movement tothe.. movable.

: member.

3. A compass unit. including, a.housing,and.a. semi-spherical compass element magnetically- I controlled mounted axially withinsaidhousing..

said element having a portionbf its. outer surface of nonlight-reilecting materialand the. remainder thereof of a light-reflecting. material,` one of said materials being in the form of anar-.- row strip extending from the. pivotaxis. to. the outer edge ofsaid. compass element.`

4. A compass unit including, a housing, a supporting. block closing the lower end.thereof,ja carrier rotatably mounted on said. block and" arranged to berotated by gravity toa predetermined position relative to thelow side. of. a well bore wheny the unit is. lowered thereinto, a.. weighted compass. support pivotally secured' to the carrier, saidcompassmember. being ,substantially semi-spherical in shape and having its'. outer surfaceof nonlightfreecting material,l and' a latitudinalstrip'. of lightreecting materiali ses cured to. the outer surface of the member and' extending from the axis'of rotation to the outer' edge thereof.

5; A compass'unitv including; a housing; and a' semi-spherical compass element magnetically controlled mountedaxially within said housing; said element havingits outersnrface ofl lightsreflecting material, and a latitudin'al strip of noir-l reiiecting material following the contour of 'tile outersurface of "the compass element anciextemi'` 

